1. Field of the Invention
Field of the present invention concerns a stand for supporting a two wheeled vehicle.
Prior art concerning a method for supporting a two wheeled vehicle is presented in Japanese Patent Application Publication No. 53-4564 and is best explained with reference to FIG. 1 herein.
In FIG. 1 a main stand 103 and a circular segment gear 106 are fixed to a common support shaft which is rotatably supported by bearings in a bracket 102 attached to the main frame 101. A worm gear 105 attached to the motor 104 drive shaft, meshes with the circular segment gear 106 and, by the rotation of the motor 104 through the worm gear 105 and the circular segment gear 106, the main stand 103, shown in the retracted position by full lines, can be rotated to the upright position indicated by broken lines. Conversely rotation of the motor 104 in the opposite direction causes the main stand 103 to move back to the retracted position.
The problem with this conventional method of supporting a two wheeled vehicle is due to the load experienced by the motor 104. In the course of the main stand 103 moving from the retracted position to the upright position, the load it puts on the motor 104 varies. In the first instance the main stand 103 swings down with almost no resistance and the load on the motor 104 is affected negligibly, but when the end of the main stand 103 touches the ground there is a sudden increase in load on the motor 104 as it starts to lift the vehicle. At this point the load on the motor 104 is a maximum. Then as the main stand 103 comes close to the perpendicular position the load decreases. This load change gives a corresponding change in the electrical current load on the motor 104 as shown in FIG. 2.
At the start of drive shown as stage I in FIG. 2, the current first rises sharply. This is due to the motor 104 starting current characteristics and not related to the drive mechanism. The load current then settles to a low value (stage II) as the main stand 103 swings down. Then when the end of the main stand 103 touches the ground the load current increases suddenly (stage III) due to the sudden increase in load on the main stand 103. The current at this time is seen to be well over the starting current peak. Then as the main stand 103 comes to the upright position, it commences to lift the body of the vehicle. During the lifting period, the peak current remains at a relatively high value (stage IV) and from the point when the main stand 103 becomes perpendicular, the load current decreases abruptly (stage V).
Due to the characteristic of the load current peaking at stage III during the operation of the stand the following problems result:
(1) It is necessary to have the motor capacity large enough to ensure that the motor capacity is at all times sufficient to carry the maximum peak load.
(2) The peak load puts extra load on the drive components so that they must be designed strong enough so their endurance and reliability is sufficient to carry this peak load.
(3) Since it is possible that the peak load surge will have an influence on other electrical loads supplied from the same power source it is necessary to have the power source large enough to provide for this additional peak load.